8 bit vs 16 bit retouching

8bit vs 16bit banding issue
8bit vs 16bit banding issue

Retouching in 8bit vs 16bit always been a discussion between retouchers and photographers, people usually ask, shall I edit in 8bit or 16bit and what’s the price for doing so.

There are a lot of articles explaining the difference between both types in details, that’s why am not going to but here is a small information you need to know before we go ahead:

  • 8 bits per channel give 256 colours per channel, and an RGB image of 24 bit.
  • 16 bits per channel give 32,769 colours per channel, and an RGB image of 48 bit.

With the huge difference in colour range between both types, it explains how much color depth 16bit have which means more freedom while editing specially if you was planning to go for heavy retouching like composite image (photo manipulation) or a low key image with lots of shadows/blacks.

File size vs colour range

The question here, if the 16bit have more colour range why I just don’t go ahead and use it all the time!!!
16bit will cost you hard disk space and PC performance. The problem began when I started to do heavy retouching in my recent shoots, I’m using Nikon D610 which mean the raw file is 24MB and once I open the raw file in Photoshop in 16bit mode the file size almost 170MB, I duplicate the original layer, applied frequency separation action (which means 2 more layers) and guess what !! I have reached 500MB and I didn’t even start retouching yet.

Screen shot from a beauty retouching
Screenshot from a beauty retouching

The image above¬† show the normal flow in any of my beauty retouching and here we are talking about 20+ layers¬† which means reaching a huge file size easily. I’m not using a super PC, and if this how its starts then the file will reach 2 GB by the end of retouching based on my flow which will make my PC almost freezes.

Solution

  • Flatten Image after each change
  • Use 8 bit

None of these works for me, I work in a non destructive way, which mean if I want to revert back any changes I have made, I can do that without affecting any of the other changes as each one exist on a separate layer. And if I used 8bit , I might see the banding problem( As it shows in the first image) which is one of the biggest problems when it comes to editing in 8bit mode, the video below is showing the banding problem when creating 2 curves layers cancelling each other to show the gradient layer below.

As you see by the end of the video you can see that converting the image to 16bit it solve the banding problem, so the solution now is up to you, based on how these pictures will be used! Is this picture is going for print! Small or large scale ! Are you going to do heavy retouching ! Is your image is having a lot of dark and black areas! or all these points doesn’t matter as drive space and PC performance is not a big deal.

In my case If am going to do heavy retouching, I start with 8bit, my PC still fresh and can breath and if I start to find any banding problem while heavy retouching, I use a script to do Dithering after converting the image to 16bit and that would solve the banding problem. If I know that this picture is going for print I will start retouching it in 16bit without a doubt. So its a matter of individual decisions about each image. This is works for me with the limitations I do have.

You can find the action script I mentioned above here Amgad Fahmi No Banding

Share with us if you came across the same problem!! and what was your decision.